Manifolds for air conditioner condensers have been made by fastening plugs in ends and mid-regions of a cylindrical tube to divide the tube into chambers, and then punching and perforating holes along the length of the tube to receive the ends of smaller tubes, which are brazed or soldered into each hole. This suffers from many problems that have remained unsolved.
If the holes are formed in a cylindrical tube without first punching out a slug of material, the tube cracks during the forming process. Punching out a slug at each hole solves this problem, but requires removal of the slugs through the holes from which they were punched, because the tube contains the chambering plugs, which cannot be inserted after the holes are punched. Slug removal is not only expensive, but causes defective parts when unremoved slugs are left within the tube.
Cylindrical collars formed around the punched holes are thin, and often cracked and delaminated. They are sometimes not accurately round, and their open ends, recessed into the tube, are curved and irregular, rather than flat. The axial length of the inside cylindrical portion of the collars is also relatively short, and all these circumstances contribute to unreliable brazing or soldering so that joints leak. This is especially troublesome in automotive air conditioners that are subject to vibration.
I have devised a way of forming condenser manifolds to overcome these problems. My manifold has hole collars that are thicker, more uniform, extend their cylindrical insides for a longer axial length, and are uncracked and flat at their open ends so that joints with tube ends are much more reliable. My forming also does not produce any slugs that must be removed from inside the tube, and my manifold tubes are easier to work with. The overall result, is an air conditioner condenser manifold that performs better without costing more.